flexpaneldid: A Stata Toolbox for Causal Analysis with Varying Treatment Time and Duration
IWH Discussion Papers,
The paper presents a modification of the matching and difference-in-differences approach of Heckman et al. (1998) for the staggered treatment adoption design and a Stata tool that implements the approach. This flexible conditional difference-in-differences approach is particularly useful for causal analysis of treatments with varying start dates and varying treatment durations. Introducing more flexibility enables the user to consider individual treatment periods for the treated observations and thus circumventing problems arising in canonical difference-in-differences approaches. The open-source flexpaneldid toolbox for Stata implements the developed approach and allows comprehensive robustness checks and quality tests. The core of the paper gives comprehensive examples to explain the use of the commands and its options on the basis of a publicly accessible data set.
Taking the First Step - What Determines German Laser Source Manufacturers' Entry into Innovation Networks?
International Journal of Innovation Management,
Early access to technological knowledge embodied in the industry’s innovation network can provide an important competitive advantage to firms. While the literature provides much evidence on the positive effects of innovation networks on firms’ performance, not much is known about the determinants of firms’ initial entry into such networks. We analyze firms’ timing and propensity to enter the industry’s innovation network. More precisely, we seek to shed some light on the factors affecting the duration between firm founding and its first cooperation event. In doing so, we apply a unique longitudinal event history dataset based on the full population of German laser source manufacturers. Innovation network data stem from official databases providing detailed information on the organizations involved, subject of joint research and development (R&D) efforts as well as start and end times for all publically funded R&D projects between 1990 and 2010. Estimation results from a non-parametric event history model indicate that micro firms enter the network later than small-sized or large firms. An in-depth analysis of the size effects for medium-sized firms provides some unexpected findings. The choice of cooperation type makes no significant difference for the firms’ timing to enter the network. Finally, the analysis of geographical determinants shows that cluster membership can, but do not necessarily, affect a firm’s timing to cooperate.
Network Formation: R&D Cooperation Propensity and Timing Among German Laser Source Manufacturers
IWH Discussion Papers,
Empirical evidence on the evolution of innovation networks within high-tech industries is still scant. We investigate network formation processes by analyzing the timing of firms to enter R&D cooperations, using data on laser source manufacturers in Germany, 1990-2010. Network measures are constructed from a unique industry database that allows us to track both the formation and the termination of ties. Regression results reveal that a firm's knowledge endowment (and cooperation experience) shortens the duration to first (and consecutive) cooperation events. The previous occupation of strategic network positions is closely related to the establishment of further R&D cooperations at a swift pace. Geographic co-location produces mixed results in our analysis.
Foreign Investors and Domestic Suppliers: What Feeds Positive External Effects?
Wirtschaft im Wandel,
The empirical study analyses the potential for positive external effects from foreign investors in favor of domestic firms using the IWH-FDI micro database and taking into account firm-specific characteristics of foreign investors in selected Central and East European countries as well as in Eastern Germany. The analysis shows that only half of the foreign investors believe that they are important for technological activities in domestic supplier firms. Thereby, the potential for external positive effects is higher in Central and Eastern Europe than in Eastern Germany. A reason for this might be that supplier firms in Eastern Germany already operate on a clearly higher technological level than their counterparts in Central and Eastern Europe. Taking into account the share of domestic supplies of foreign investors, it shows that the potential for positive external effects increases only to a certain point from which on the spillover potential stagnates or even declines. Furthermore, there is clear evidence for the following characteristics of foreign investors to increase the potential for positive external effects: innovativeness of the foreign investor, internal and external technological cooperation of foreign investors, independence from the headquarters in research and development issues and market entry through acquisition (instead of greenfield investment). The share of foreign participation as well as the duration of presence in the host economy does not show any statistically significant effect on the potential for external effects. Policy makers should therefore not only aim at the settlement of employment intensive foreign investors, but also and particularly support investors that are characterized by technological activity and regional integration.
Evaluation of Further Training Programmes with an Optimal Matching Algorithm
IWH Discussion Papers,
This study evaluates the effects of further training on the individual unemployment duration of different groups of persons representing individual characteristics and some aspects of the economic environment. The Micro Census Saxony enables us to include additional information about a person's employment history to eliminate the bias resulting from unobservable characteristics and to avoid Ashenfelter's Dip. In order to solve the sample selection problem we employ an optimal full matching assignment, the Hungarian algorithm. The impact of participation in further training is evaluated by comparing the unemployment duration between participants and non-participants using the Kaplan-Meier-estimator. Overall, we find empirical evidence that participation in further training programmes results in even longer unemployment duration.
IWH FDI Micro Database
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Establishing Evidence-based Evaluation Methods for Subsidy Programmes in Germany (EVA-KULT)
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